Great re-visiting of the thread, because excuses change over time, if our wives don't.

"Everyone needs a beautiful shiny old bike" 1982 Lotus
"It only fits me, and no one will buy it" 1995 Hot Tubes TT
"I have to keep an old Italian steel around to ride with Rick" 1987 D'Arienzo/Basso
"It's rare, I've never seen another, and it's not new" 2006 Cinelli (carbon, requires multiple excuses)
"I'm going to sell it, don't worry" 2008 BMC
"I'm going to sell it, don't worry" 2011 Merckx
"This replaced 3 bikes, and has led to downsizing. You should thank it" 2014 Wraith Hustle
"This will replace 2 more bikes, and will prevent rough riding on my other grey bike" pending 2014 Wraith Paycheck